This still baffles me, and I know we've all been there. You show up to class a minute or two late (on time in my book), and it's like your classmates have built a human wall blocking you from all the seats. One person in the aisle seat of a row effectively nullifies all the seats in that row.
We usually have two options when we face this dilemma:
1. Sit in the way back where no one has dared venture.
2. Awkwardly squeeze by the sociopath in the aisle seat as they gingerly move their knees and act extremely inconvenienced by slightly lifting their computer. This raises a whole other set of problems, as Tyler Durden taught us. Specifically: "Now, a question of etiquette - as I pass, do I give you the ass or the crotch?"
Proper seating manners are an essential part of any civilization. I'd appreciate it if we all learned them correctly. It would also make my late entrances less conspicuous...